The invention relates to an apparatus for the continuous winding of a web of sheet-like material, in particular a paper web onto a roll core, comprising a carrying drum guiding the web, a transfer device for transferring the empty roll core out of a holding position into an operative position, a drive for the roll core, a support and transport device operative during the winding operation for moving the roll core to discharge the fully wound roll core, and a device for transferring the conveyed web from the fully wound roll core onto an empty roll core.
In connection with such an apparatus, a so-called poperoller is known. The continuous winding of a paper web is possible with such a poperoller. In this case, the paper web is guided around a carrying drum and then wound onto a roll core, a so-called tambour. The winding drive is carried out such that the previously mentioned roll core is driven and lies at the outer periphery of the ensuing winding. A swivel arm is arranged approximately concentrically to the carrying drum, by means of which swivel arm an empty roll core can be brought into the winding position when the previous roll core has been fully wound with the paper web. The transfer of the fully wound paper web onto the empty roll core ensues automatically without having to completely interrupt the operation as a whole. The accomplishing of the winding drive via the carrying drum at the periphery of the ensuing winding is associated with certain disadvantages regarding the winding quality.
The U.S. Pat. No. 4,744,526 describes a winding apparatus which is also able to work continuously during roll changes, the winding apparatus comprising a carrying drum.
A winding apparatus for winding pressure-sensitive paper is known from DE-A-29 35 743 or EP-A-26 335. This winding apparatus makes use of a first pressing roll which is held at a distance from the winding. In the direction of feed of the paper web, a second pressing roll having a soft pressure applying surface is provided behind this first pressing roll. On account of the distance between the first pressing roll and the winding, air is drawn into the winding, particularly at high machine speeds. The drawing-in of this air is prevented by the second pressing roll. Thus, the second pressing roll having a soft surface lies against the surface of the winding under slight pressure. When the winding increases, the position of the second pressing roll is shifted and a switch is actuated which serves to move forward the roll core on which the web is being wound. Thus, a gentle, soft winding without the inclusion of air results. This means that although a good winding quality is provided, the possibility of continuing to wind during roll changes is not provided. For example, no carrying drum is included which is important for the continuous operation for roll changes.
Should the continuously operating roller according to U.S. Pat. No. 4,744,526 be combined with the teaching of the application referred to above, a very complicated apparatus would result.
In DE-A 1 560 039, a different solution for achieving a uniformly applied pressure is suggested by means of the application of a withdrawal roll and a pressure roll. However, a continued winding during the roll change is also not possible in this case.
It is an object of the invention to achieve a soft winding process in connection with the poperoller-system initially mentioned in order to realize a homogenous and gentle winding process across the entire width of the winding.
This object is solved in accordance with the present invention in that the carrying drum is arranged as a guiding drum in such a manner that it is always located at a distance from the winding, that a pressing roll is provided behind the guiding drum in the running direction of the web and is arranged in such a manner that it always lies against the winding during operation, that the pressing roll is connected with a sensor for determining the increase in the winding, that the support and transport device for the roll core is connected with a drive controlled by the sensor, and that a separate winding drive is provided for rotating the roll core.